How to use the FFT algorithm

Hello,

I want to usethe FFTalgorithm from C67xDSPLIBlibrary. I work on DSP core of OMAP-L137 processor.
I chosefunction: void DSPF_sp_cfftr2_dit (float * x, float * w, short n),
where:

  x - pointer to complex data input.
  w  - Pointer to complex twiddle factor in bit-reverse order.
  n  - Length of FFT in complex samples, power of 2 such that n ≥32 and n<=32K.

SPRU657.pdfsays how to use it:

  void main(void)
  {
    gen_w_r2(w, N); // Generate coefficient table
    bit_rev(w, N>>1); // Bit−reverse coefficient table
    DSPF_sp_cfftr2_dit(x, w, N);
        // input in normal order, output in
        // order bit−reversed
        // coefficient table in bit−reversed
        // order
  }

Buthow to preparethe x andw.Whatmathematical operations(functions)should be used.
I havesamples froman ADC converter and what must I do toreplace them tovectorsx andw?